Gabapentin (1-aminoethyl-cyclohexane acetic acid) is currently commercialized for the treatment of epilepsy. The compound has however been recognized as being also useful for the treatment of pain and anxiety.
Recent reports have suggested an interaction between gabapentin and the α2δ subunit of a voltage-dependent calcium channel (VDCC). But electro-physiological studies have yielded conflicting data on the action of gabapentin at VDCCs, even though the relevance of the interaction of gabapentin at the α2δ subunit to the clinical utility of the drug is becoming clearer. However, none of the prototype anticonvulsant drugs displace [3H]gabapentin binding from the α2δ-1 subunit.
The most frequently used assay currently available for the screening of ligands that bind the α2δ subunit involves the use of pig membrane extracts as a source of the α2δ subunit. Such an assay presents major inconvenience. Firstly, because the assay material is a membrane extract, it is very difficult to accurately determine the protein composition from one assay preparation to another particularly with regard to the subtype. Also, the presence of various impurities in the assay preparation is a problem in small plate assays. Furthermore, as the protein preparation lacks homogeneity, the interaction between the targeted protein and the assay plate is often quite uneven. This renders the streamlining of the assay in a high throughput format almost impossible to achieve.